Neuropsychological dysfunction in children with chronic low-level lead absorption.

To investigate the relation between low-level absorption and neuropsychological function, blind evaluations were under-taken in forty-six symptom-free children aged 3-15 years with blood-lead concentrations of 40-68 mug. per 100 ml. (mean 48 mug. per 100 ml.) and in seventy-eight ethnically and socioeconomically similar controls with levels greater than mug. per 100 ml. (mean 27 mug. per (100 ml). All children lived within 6-6 km. of a large, lead-emitting smelter, and in many cases residence there had been lifelong. Mean age in the lead group was 8-3 years and in the controls 9-3. Testing with Wechsler intelligence scales for schoolchildren and preschool children (W.I.S.C. and W.P.P.S.I.) showed age-adjusted performance I.Q. to be significantly decreased in the group with higher lead levels (mean scores, W.I.S.C. plus W.P.P.S.I., 95 v. 103). Children in all ages in the lead group also had significant slowing in a finger-wrist tapping test. Full-scale I.Q., verbal I.Q., BEHAVIOUR, AND HYPERACTIVITY RATINGS DID NOT DIFFER.